An estimated 1 million Americans (and more than 90,000 New York City residents) have HIV infection. Despite recent advances, HIV/AIDS remains an important area for clinical investigation. This application describes the Cornell Clinical Trials Unit (CCTU), an HIV/AIDS therapeutic clinical trials unit that will affiliate with the 3 AIDS Clinical Trials Group (ACTG) network by prior agreement. The Cornell unit consists of an overall administrative core and two CRSs: Cornell Uptown and Cornell Chelsea. The core unit provides central research support to the CRSs including: investigative oversight, administration, study coordination, data management, regulatory, outreach, and pharmacy services. The two clinical research sites CRSs are located in different parts of New York City, in or close to the neighborhoods with the highest HIV seroprevalence rates: Cornell Uptown is located close to East Harlem (2.5% seroprevalence) and Cornell Chelsea is located in Chelsea-Clinton (4.1% seroprevalence). The two CRSs serve distinct patient populations that include significant numbers of women, people of color (African Americans, Asians, and Latinos), and adolescents/young adults from diverse risk groups (heterosexuals, injection drug users, men who have sex with men). With 17 years experience in the ACTG, the Cornell unit has broad scientific and clinical research experience in diverse areas including: antiretroviral agents and strategies; complications of HIV and antiretroviral therapies; immune-based therapies, including vaccines; co-infections (e.g. hepatitis B, hepatitis C, and human papillomavirus); neurological complications; adherence and outcomes; HIV-infected women and pregnancy; and prevention of mother-to-child transmission of HIV. The Cornell unit will contribute to the priority research areas of the ACTG: translational research/drug development; optimization of clinical management, including co-morbidities; therapeutic vaccine research and development; and prevention of mother-to-child transmission. Cornell investigators serve in ACTG leadership positions, on ACTG committees, and ACTG protocol teams (including protocol leadership for 11 current studies). Cornell has strong ties to Haiti and plays an active role in mentoring and training Haitian HIV/AIDS clinical investigators. A major focus of the Cornell unit is community outreach and education and the Cornell Community Advisory Board is active in representing our diverse community. ADMINISTRATIVE COMPONENT: